Key switch assembly



July 6, 1965 w. J. ANDERSON 3,193,607

KEY swIToH ASSEMBLY v Filed March 7, 1961 3 Sheets-Sheet 1 IN VEN TOR.li/fer .l Anw/'salz A TTORNI: YS

July 6, 1965 w. .LANDERSON 3,193,607

' KEY swITcH ASSEMBLY Filed March '7. 1961 3 Sheets-Sheet 2 IN VEN TOR.d Anderson lai/@ @W2 fx/ x A TTORNE YS' 1%/ mm. mm m M ,f y M July 6l965 w. J. ANDERSON 3,193,607

KEY SWITCH ASSEMBLY Filed March 7, 1961 3 Sheets-Sheet 5 Eid/7@ 104, 7/7%* 7/ mmm 9 9% o/ 7/ 7aa"\ l: '50a' 7/ y af INVENTOR.

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A ORNEYS United States Patent O 3,193,607 KEY SWITCH ASSEMBLY Walter J.Anderson, Elgin, Ill., assigner to Chicago Musical Instrument Co.,Lincolnwood, Ill., a corporation of Illinois Filed Mar. 7, 1961, Ser.No. 94,066 21 Claims. (Cl. 84-1.l)4)

This invention relates generally to electrical switch structure, andmore specifically to an improved key switch assembly for an electricalmusical instrument, such as of the electronic type.

Although the principles of the present invention may be included invarious devices, a particularly useful application is made in anassembly which forms a part of an electrical musical instrument, eitheras an attachment accessory, or as an integrated unit in the keyboard ofsuch instrument.

The instant invention is particularly adapted to produce musical chordson such instrument by combining various electrical signals which, whenconverted to sound, comprise various chords. When such a feature is tobe embodied in an electric organ, it is an important objective tominimize the quantity of structure necessary to do a satisfactory job.Accordingly, as will become apparent in reading the followingdescription, the instant invention is readily adapted to cooperate withother structure found in such organs, and to that end employs a minimumof parts and obtains a number of results.

A representative embodiment of the instant invention employs a number ofpush-button type of keys, each of which is associated with appropriatestructure for producing various chords. These chords include a majorchord, a dominant seventh chord, a minor chord, a diminished seventhchord, and an augmented chord. Each of these chords includes three orfour different notes,`and button keys are provided for producing thesechords kin each of the various playing keys which are most commonlyused. Where the device is constructed to play in nine different playingkeys, such device requires 153 electrical poles.

Accordingly, it is an object of the instant invention to provide a keyswitch assembly of the type described employing simplified structure.

Another object of the instant invention is to provide a key switchassembly structure wherein certain elements are employed in common withother cooperaing elements to minimize the quantity of structurerequired.

A still further object of the present invention is to provide a keyswitch structure which enables the simultaneous closing of a number ofcircuits.

Yet another object of the present invention is to provide a structurewherein contact wipe is present for maintaining the electricalcleanliness of contacting surfaces.

A still further object of the present invention is to provide a deviceof the type described wherein individual key elements or push buttonsoperate with a good feel Yet another object ofthe present invention isto provide a structure wherein a plurality of circuits aresimultaneously closed in response to movement of a key for a distancewhich is only a part of that distance which such key is movable, therebyenabling rapid playing of such device without loss of any musical tone.

A still further object of the present invention is to provide structuraldetails and relationships which minimize the labor and material costsincurred in manufacturing the same.

Many other advantages, features and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description and the accompanying sheets ofdrawings in which a preferred structural embodiment incorporating the n`ICC principles of the present invention is shown by way of illustrativeexample.

On the drawings:

FIGURE l is a top plan view of a key switch assembly for a musicalinstrument provided in accordance with the principles of the presentinvention, the figure including a schematic diagram illustrating how theinvention is ernployed in an lelectrical circuit;

FIGURE 2 is an enlarged schematic perspective diagram of the key switchassembly of FIGURE l, a portion thereof being illustratednondiagrarnmatically;

FIGURE 3 is an enlarged end elevational view of the key switch assemblyshown in FIGURE l;

FIGURE 4 is an enlarged cross-sectional View taken along line IV-IV ofFIGURE 1;

FIGURE 5 is an enlarged fragmentary View taken along line V--V of FIGURE4;

FIGURE 6 is a fragmentary illustration of key structure provided formajor chord keys, viewed in a direction normal to the plane of the keyelement thereof; n

FIGURE 7 is a fragmentary illustration of key structure provided fordominant seventh chord keys, viewed in a direction normal to the planeof the key element thereof;

FIGURE 8 is a fragmentary illustration of key structure provided forminor chord keys, viewed in a direction normal to the plane of the keyelement thereof;

FIGURE 9 is a fragmentary illustration of key structure provided fordiminished seventh chord keys, viewed in a direction normal to the planeof the key element thereof;

FIGURE 10 is a fragmentary illustration of key structure provided foraugmented chord keys, viewed in a direction normal to the plane of thekey element thereof;

FIGURE l1 is a fragmentary perspective illustration of a modifiedkey-switch structure provided for major chord keys; and

FIGURE l2 is a fragmentary illustration of a modied form of key-switchstructure provided for dominant seventh and diminished seventh chord keystructure.

As shown on the drawings:

The principles of this invention are particularly useful when embodiedin a key switch assembly for an electrical musical instrument, thevarious switches thereof being adapted to produce chords on suchinstrument, the same being illustrated in FIGURE l, generally indicatedby the numeral 15. The key switch assembly 15 includes, as best seen inFIGURE 3, an insulative frame assembly 16, an electrically conductivecollector plate 17, a series of rows of electrically conductive keyelements 18-22, nine such rows being illustrated in FIGURE l and one ofsuch rows being illustrated in FIGURE 3, an electrically conductivereturn spring 23 for each of the key elements lil-22, and a series ofelongated resiliently yieldable electric conductors 24-26.

The insulative frame 16 includes an insulative top frame plate 27, aninsulative bottom frame plate 28, an insulative front frame plate 29, aninsulative rear frame plate 30, and an insulative frame spacer plate 31.The frame plates 27-30 jointly define a hollow boX formation and areheld together by a number of brackets 32 to which suc-h plates areattached, as by screws. The spacer plate 31 is disposed in parallelrelation to the plates 29 and 3i), and is held in position by a nut andbolt assembly 33 having tubular stand-od elements 34, 35.

The electrically conductive collector plate 17 is secured between thebrackets 32 and the bottom frame plate 28, and has a number of upwardlyextending integral ears 36 which abut laterally against the plates 29-31to provide further stability for the same. A number of clips 37 securedto the plates 29 and 30 provide still further stability for the frontand rear frame plates respectively.

Each of the plates 27 and 28 is provided with a slot which receives andguides opposite ends of each of the key elements 18-22 so that each keyelement may be moved back and forth nonrotatably in such slots. Each ofthe key elements is provided with a push button 38 at its upper end, thevarious push buttons 38 projecting through a suitably apertured cover ortemplate 39 having appropriate identifying markings, such as shown inFG- URE 1. The push buttons 3S may also be marked, if desired. Each ofthe key elements 18-22 is provided with means identied at 4t) whichprovides a downwardly direct shoulder, between which shoulder and theplate 17 one of the springs 23 is disposed. Thus, each spring 23 urgesone of the key elements in an upward direction as shown, and alsoelectrically connects such key element with the plate 17.. Upwardmovement of each key element is limited by a pin 41 carried at the lowerend of each key element and projecting horizontally therefrom, a feltwasher 42 being provided between each pin 41 and the bottom frame plate28. Downward movement of each key element is arrested when thecorresponding key button 38 engages a further felt washer 43 disposed between the key button 38 and the upper frame plate 27.

Each of the electrical conductors 24-26 is secured to the insulativeframe 16 and is supported thereby. Each of the conductors 24 and 26 isdisposed adjacent to a number of the key elements, and the conductor 25is disposed adjacent to at least one of the key elements 21. Each of theelongated conductors 24-26 is thus supported in insulated spacedrelation to the various key elements 18-22, when such key elements arein their released position as shown in solid lines in FIGURES 3 and 4.The rear end of each of the electrical conductors 24426 is provided witha suitable electric connector 44 of a conventional type which supportsthat end of the corresponding conductor on the rear plate 30, and whichadapts it to be connected to the proper point in the musical instrumentcircuit described later herein.

The other end of each of the conductors 24 and 26 is supported, in thisembodiment, by the front frame plate 29, while the other end of each ofthe conductors 25 is supported by the spacer plate 31. The spacer plateV31 is suitably slotted from its upper edge to pass the variousconductors 24, and from its lower edge to pass the various conductors26, as can be seen in FGURE 2. The lower edge of the spacer plate 31,the lower edge of the front frame plate 29, and the upper edge of thefront frame plate 29 are each provided with a number of special slotsfor supporting the other end of the various conductors 24-26. In apreferred embodiment, each of the conductors 24-26 comprises anelongated helical tension spring or spring means having at one end threeprogressively larger diameters. As seen in FIGURE 5, a iirst or smallestdiameter 45 represents the diameter of the conductor throughoutsubstantially all of its length, except at the end being discussed. Asecond diameter 46 is of intermediate size and a third diameter 47 issomewhat larger. Each of the conductor supporting slots has a widthdefined by a pair of confronting faces 48 which are spaced apart by adistance which is intermediate the diameters 45 and 46. At its remote orclosed end, the slot is enlarged as at 49 to a size intermediate thediameters 46 and 47, thus deiining a keyhole type of shape. The diameterat 45 is freely received between the faces 48 and the conductor is movedinto the slot until the diameter 45 is substantially concentric will theenlargement at 49 which, because of its greater size, freely admits theintermediate diameter 46. Since this diameter is larger than the width48, that end of the conductor canductor cannot slip out through theslot, and the larger turns 47 serve as a stop against the outside of thefront frame plate 29. Since the diameter at 46 is greater than that at45, it has a lower spring rate so that the turns at 46 expand andtension the conductor, while the turns at 45 remain closed.

FIGURE 6 illustrates one of the key element 18, it being shown in thereleased position. The key element 18 has electrically conductiveengaging arm means 18a and 1gb secured thereto which extend transverselyto the conductors 24, and transversely to the direction in which the keyelement 18 is reciprocable. Depression of the key element 18 effectssimultaneous engagement of a plurality of the conductors 24 bytheengaging arm means, thus closing the circuits from each of theconductors 24 so engaged, to the collector plate 17.

FIGURE 7 illustrates the key element 19 which has electricallyconductive engaging arm means 19a, 19b, and 19C which also extendtransversely to conductors 24 and 26, and transversely to the directionof key reciprocation. Key elements of this type engage a plurality ofconductors simultaneously to close the circuits from them to the plate17. Where signal frequencies are applied to the conductors 24 asindicated by the notes C, E, and G on FlG- URES 6 and 7, depression ofthe key element 18 effects production of a major chord or triadconsisting of those notes. It will be noted that the same conductors 24are engaged by the key element 19 to produce the same major chord, andin addition, since the arm means 19e engages a conductor 26 which isprovided with a signal having a frequency corresponding to the note Bflat or the dominant seventh note for the musical key of C, depressionof the key element 19 produces a dominant seventh chord.

FIGURE 7 also illustrates a feature common to all of the key elements,namely that the engaging arm means come into physical contact with theproper electrical conductors after the key element 19 has been depressedapproximately one-half or two-thirds of its available travel. Thisrelationship insures that the chords will be produce when the instrumentis played rapidly, without full bottoming ofthe corresponding buttons38.

The spring 23, when assembled as shown in FIGURE 6, is in a compressedstate, and as it is compressed further to the positions shown in FIGURES7 and 8, the increase in force needed to operate the key element isimperceptible to the user. The force delivered by the spring 23 thusalso is somewhat larger than the force required to deflect a group ofconductors from their substantially free position, as shown in FIGURE 7,to a deflected position, as shown in FIGURES 4 and 8.

FIGURE 8 shows the structure employed to produce a minor chord, andincludes one of the key elements 20. The key element 20 is provided withelectrically conductive engaging arm means 20a, 2019, and 20c. Theengaging arm 20h is provided with an insulator or insulator sleeve 50which prevents picking up any signal from the i E spring, as is desiredin FIGURES 6 and 7. The er1- gaging arm 20c engages one of theconductors 26 which provides a signal having a frequency correspondingto the pitch of the iiatted third note of the chord. The engaging armmeans 20a-20c are otherwise similar to those described above.

FIGURE 9 shows the key structure employed for producing diminishedseventh chords. This structure includes the key element 21 which hasengaging arm means 21a, 2lb, and 21e. The arm means 21a is engageablewith two of the conductors 24, the arm means 2lb is engageable with oneof the conductors 25, and the arm means 21e is engageable with one ofthe conductors 26. These arm means extend transversely to theseconductors, transversely to the direction of key element reciprocation,and collectively engage a plural-ity of conductors simultaneously.

FIGURE 10 illustrates the key switch structure employed in thisembodiment to produce augmented chords. This structure includes the keyelement 22 which is provided with engaging arm means 22a, 22b, and 22C.The engaging arm means 22a and 22h engage two of the conductors 24, andthe engaging arm means 22e engages one of the conductors 26. The variousengaging arm means 22a-22o engage the Various conductors simultaneously.

It will be noted that each of the engaging arm means 19C, 20c, 21e, and22e` is vertically spaced from the corresponding conducting arm means19a, 20a, 21a, and 22a respectively. This vertical spacing issubstantially the same as that which is provided between the conductors24 and the conductors 25, 26. Thus, as best seen in FIG- URES 9 and l0,when the various keys are in the released position as illustratedtherein, the actual clearance between the engaging edge of the engagingarms and the cooperating electrical conductors 24, 25, and 26, isidentical, whereby simultaneous engagement or closing of the variouscircuits occurs.

It will also be noted that the engaging arm means of the various typesof key elements illustrated herein each includes a pair of oppositelydirected arms which, with the main portion of the various key elements,forms a cross.

All of the conductors 24 are disposed parallel to each other andparallel to each of the rows of tive keys. This relationship is best`seen in FIGURE 2 which illustrates the locations of the variousconductors and identities them. In this embodiment, all of theconductors 24 lie in one plane and jointly comprise a first means whichis spaced a first distance from the conducting plate 1'7. All majorchords or major triads are formed using three consecutive conductors 24.The additional conductors 25, 26 jointly comprise a second means whichis spaced a second distance from the plate 17, which in this embodimentis a lesser distance. The conductors 26 are disposed parallel to eachother and thus also lie in a common plane, but they extend transverselyto three adjacent rows of five keys. In view of this conductordistribution, it is preferable also to dispose the conductors 25parallel to each other and in the same plane as the conductors 26 forproviding the flatted fifth note to the various diminished seventhchords. The conductors 25 are thus transverse to the appropriate row ata point adjacent to the various diminished seventh key buttons. f

The conductors 26 each provide a dominant seventh note of one of thedominant seventh chords, and may ytherefore: be termed as dominantseventh conductors. However, this is merely a term of reference, sincethe same conductor provides three other notes for three other chords.This set of conductors is also employed to provide the flatted thirdnote of the minor chord and the fla-tted third note of the diminishedseventh chord, as well as the raised fifth of the augmented chords.Therefore, this conductor may also be termed as a flatted thirdconductor and as an augmented fifth conductor.

Referring to FIGURE 2, it will be noted that all of the C chords aredisposed in a row, that all of the G chords are disposed in a row, etc.It will also be noted that all of the major chords from each row arealigned, that all 'of the dominant seventh chord buttons of each row arealigned, etc. Beginning with the key of C row, the next 4increase onesharp for each row to the right, and by one tiat for each row to theleft. `would ordinarily prefer to play on a conventional key- Mostt-rained musicians board, but the chord key switch assembly of thisinvention is provided primarily forA the amateurs and novices.

,It is thus practical to omit structure for produc-ing chords Aforplaying keys having tive, six, or seven Sharps or flats,

such being ordinarily beyond the scope of the musician who would usethis invention to greatest advantage. Moreover, only a very smallfraction of music which is written is composed in those difficult keys.In any event,

`it will become readily apparent to one who has studied this descriptionthat the pattern established in FIGURE 2 may be extended or contractedat either end to adapt a particular embodiment to the level of music ormusicianship desired.

To produce a C major chord, it is necessary to combine signalfrequencies of the C note, the E note, and the G note. The C note is theroot note, the E note is referred to as a third note, and the G note isreferred to as the fth or fifth-note. Thus, as best seen in FIGURES 2and 6, one of the conductors 24 extends to the left of the C majorbutton to provide :a signal whose frequency is that of the C note, andtwo additional conductors 24 extend to the right of the C major buttonto provide the third and fifth note frequencies. This chord is thenproduced by depression of that button, the structure utilized beingshown in FIGURE 6. These same three conductors extend in the same mannerin the `same relative position adjacent to all of the key elements inthe C row. The C or root conductor is engaged by all of these keyelements, the E or third yconductor is engaged by the key elements ofthe major, dominant seventh, and augmented chords, and the G conductoris engaged -by the major, dominant seventh, and minor chord-s. Since thekey element of the minor chord must engage the fifth note conductor, andnot the third note conductor, insulation means are provided, asexplained, to avoid including signal `from the third note conductor.Thus, it will be readily understood that the engaging arm means 2Gb maybe appropriately shaped so that the insulator -comprises an air gapbetween the engaging arm 2012 and the third note conductor.

With the keyboard arranged in this manner, it will be noted that the fthnote of each chord is the root note of the next adjacent chord to theright. This is true for each pair of adjacent rows. Thus the G note orfifth note conductor for the C row is also engaged by all tive of thekey elements ofthe G note row, since it is the root note thereof. Thusthe C, G, D, etc. conductors `24 are each engaged by eight key elements,and the third note conductors 24, such as E, B, Fit, Cit, etc. areelectrically engaged by only four key elements. Thus, each key element118 is engageable with a group of three adjacent conductors 24 whichdefine a major triad, consisting of the root, third, and fifth notes,and the other four key elements in the same row engage the same root andcertain other of these three conductors. Thus, also, the fifth noteyconductor of each row is the root note conductor for all of the chordsof the next row to the right, whereby two adjacent rows employ the sameconductor 24.

It is to be noted that the third note conductor of each major chord isalso engaged by the key element 21 of the adjacent row to the right sothat the conductor which provides the third of the major, dominantseventh, and augmented chords al-so provides the diminished seventh noteof a chord whose root is a fifth higher. Thus the third and fifthconductors of the C major chord are also utilized as the root anddiminished seventh 4conductors of the G diminished seventh chord. Thusthe third note condu-ctors 24 are each electrically engaged by not onlythe three previously described key elements, but also by a fourth keyelement in the adjacent row. Each dominant'seventh note conductor 26 isused to provide the dominant seventh note in one row, the atted thirdnotes of the minor cho-rd and the diminished seventh chord in` the nextrow to the right, and the raised fifth of the augmented chord of thestill next row to the right, each row to the right 'being a fifth higherthan the preceding row. A diminished chord, without the seventh note,can be provided by shortening the length of the engaging arm means 21aso that it does not engage that conductor 24 which provides thediminished seventh note. However, it is preferred to construct thedevice as shown and described since the diminished seventh chord is aparticularly beautiful chord.

As a musician gains experience with this device, he will ldiscover thatcertain combinations of buttons may be simultaneously depressed toobtain further chord combinations which .are particularly beautiful. Ineach of these, a

portion of the chord may be added or removed without disrupting the restof the chord. To illustrate, assume that the C major chord button hasbeen depressed, thus simultaneously effecting the sounding of C, E, andG. With this arcano? chord being held, the C dominant seventh chordbutton may also be pressed, thus adding the ydominant seventh note tothe chord, which note may be removed and added lat will Withoutdisturbing the production of the tone-s cfomprising the major chord.This freedom from disturance is brought about the nature of thestructure employed. It can be seen in AFIGURE 4 that when any button isfully depressed, the various conductors engaged by it will deflect fullyonly at that particular button, and will be displaced only partiallyadjacent to any other button. When -such other `button is depressedwhich .is to come in contact with one or more of the same conductors,there is still some travel `or deflection possible also at that `otherkey element, and thereafter, either button may be raised withoutdisturbing the continuities present at the other button which engagesthe same conductor.

A further unusual or unexpected combination may be achieved by firstdepressing one of the major chord buttons, lor its dominant seventhchord button, and thereafter or simultaneously therewith depressing theminor chord button of the next row to the right, whose root note is afifth higher, to thereby add the ninth note to the dominant seventhchord, or to add the dominant seventh note and the ninth. note to themajor chord. The resulting livetone chord is beautiful, unusual, andoften awkward to play with one hand `on a conventional keyboard, due tothe spacing of keys. The addition of a ninth in that manner presupposesthat the device as a whole will be used with signal lsources of suitablefrequencies. In this example also, the conductors which are engaged byboth of the key elements involved, will yield initially, :and will yieldfurther in response to actuation of the second key.

The instant device can be used to advantage when connected to twelvesuitable tone generators or signal sources of various frequenciesrepresented by a chromatic scale. Each signal source is schematicallyindicated at 51 and may comprisev a low impedance source. Each signalsource 51 is connected through a current limiting resistor 52 to Ianappropriate terminal -on the device 15 by means of a number yof wireswhich are -collectively brought to- `gether as a cable 53, wherein theindividual wire-s are insulated from each other. Each wire is thenconnected to terminals in accordance with markings indicated on FIG- URE2. Where only twelve signal sources are employed, all of the conductors24-26 having the same note, are connected together as shown. By thisstructure, certain chords will be inverted. However, if it is desired toavoid inversion, -additional signal sources 51 may be employed (whichare already present in most organs), each being connected to theappropriate conductors 24-26 directly, the various jumper wires 54 thenbeing omitted.

The conductive plate 17 is provided with a terminal 55 to which a wire56 is connected, which is maintained above ground by a resistor 7. Thewire 56 is connected through a coupling capacitor 58 to a junction point59 which is common with one side of a number of tab switches or stops60. Each of the switches 60 controls various paths that the signal maytake through a series of voicing circuits 61 of a known type, the outputof which is amplilied as at 62 for being converted into sound by aspeaker 63. Where the instant invention is used as an attachment, or incombination with other manuals for producing similar pitched notes,signals from such other manual may be brought into the circuit by a leadwire 64 communicating with the junction point 59.

A typical value for the resistor 52 is 800,000 ohms, for resistor 57 is200,000 ohms, and for the capacitor 58 is .02 mfd.

It is now evident that the disclosed embodiment may be used to combinetwelve signals in forty-five different ways, that the number of signalsto be combined and that the number of ways of combining them can beexpanded, that the signals which are combined by the depression of anykey button are each simultaneously initiated, that the instantembodiment discloses 153 separate switches each of which has a rubbingaction with the various key elements for maintaining cleanlinessthereof, that the various key buttons all have a uniform feel as betweeneach other and as each button is deected, and that the various buttonscan be played rapidly with the resulting chords produced without fulldisplacement of the buttons.

Referring now to FIGURE l1, there is illustrated an alternate form ofconductors. A pair of spaced insulative frame plates 66 supports aplurality of conductors 67 of the solid type, each of which is fittedwith a resilient spring 68 at each end thereof, the spring 68 at one endof each of the conductors 67 being adapted to be connected to a suitablesource of signal, as described before. Displacement of the key element18 effects an engagement between the engaging arm means 18a, 1811 andthe various conductors 67. In response to such engagement, theconductive spring means 68 thereof yield to permit additionaldisplacement of the key element 18.

FIGURE 12 illustrates a further modification which includes a number ofrigidly supported rigid conductors 69, shown in cross-section, andsupported by a frame structure (not shown) similar to that disclosed anddescribed, which reciprocably supports a key element 70. The key element70 is provided with a number of arms 70a, each of which has a spring orelongated resiliently yieldable electrical conductor 71 secured thereto.When the key element 70 is displaced, the various springs 71 will yieldafter they have been engaged, to thereby permit further displacement ofthe key element 70.

In FIGURE 2, it will be noted that one ofthe shorter conductors 25 isdisopsed between each adjacent pair of the longer conductors 2d, theendmost conductors 26 being abbreviated in length and supported by thespacer plate 31. In order to adequately describe the conductor 25 inrelation to FIGURES 3 and 4, reference to the shortened E conductor 26has been omitted above. The appearance of the shortened E conductor 26is identical to the illustrated conductor 25.

Although various minor modifications might be suggested by those versedin the art, it should be understood that I wish to embody within thescope of the patent warranted hereon all such embodiments as reasonablyand prpperly come within the scope of my contribution to the ar I claimas my invention:

1. A key-switch comprising in combination: an electrically conduciveplate; an electrically conductive key element reciprocably supported inelectrical contact with said plate; a pair of separate electricalconductors disposed adjacent to but spaced different distances from saidkey element and electrically insulated therefrom and from each other;and an electrically conductive arm electrically conductively secured tosaid conductive key element and extending therefrom transversely to saidconductors and transversely to the direction in which said key elementis reciprocable and selectively engageable simultaneously with both saidconductors in response to reciprocation of said key element; and aninsulator engageable with both said arm and that one of said conductorswhich is nearer to said key element in a manner to preclude electricalcontinuity therebetween during said engagement.

2. A key-switch comprising in combination: an electrically conductiveapertured plate; an electrically conductive key element reciprocablysupported in electrical contact with said plate and extending throughthe aperture thereof: an elongated helical electrically conductiveextension spring Contact rigidly supported at both its ends and disposedadjacent to said key element and electrically insulated therefrom; andan electrically conductive engaging arm electrically conductivelysecured to said key element and extending therefrom transversely to saidspring contact and transversely to the direction in which said keyelement is reciprocable and selectively engageable with said springcontact in response to reciprocation of said key element, said springcontact being yieldable intermediate its ends in response to beingengaged by said engaging arm.

3. A key-switch comprising in combination: an insulative frame having aslot; a separate electrically conductive apertured plate supported bysaid frame; an electrically conductive key element reciprocablysupported by said insulative frame in electrical contact with said plateand extending through the aperture thereof; and an electrical contactcomprising an elongated helical conductive extension spring supported atboth ends by said frame and disposed adjacent to and insulated from saidreciprocable key element; said key element having an engaging armextending therefrom transversely to said spring contact and transverselyto the direction in which said key element is reciprocable, andengageable with said spring contact, said arm being electrically coupledthrough said conductive key element to said conductive plate; saidhelical contact spring having wire turns of three progressively largerdiameters all at one end thereof; said frame slot being of a widthintermediate the two smaller turn diameters receptive of only thesmallest diameter and terminating at its closed end in an opening of asize intermediate the two larger turn diameters and receiving andsupporting the intermediate diameter size turn.

4. A key-switch comprising in combination: an insulative frame; aseparate electrically conductive apertured plate supported by saidframe; an electrically conductive key element reciprocably supported bysaid insulative frame in electrical contact with said plate andextending through the aperture thereof; and an electrical contactcomprising an elongated helical conductive extension spring supported atboth ends by said frame and disposed adjacent to and insulated from saidreciprocable key element; said key element having an engaging arm,extending therefrom transversely to said spring contact and transverselyto the direction in which said key element is reciprocable, andengageable with said spring contact, said arm being electrically coupledthrough said conductive key element to said conductive plate.

5. In a switch assembly having an electrical helical contact spring, theimprovement comprising: a series of wire turns all at one end of theelectrical contact spring of three progressively larger diameters; and asupport member having a slot of a width intermediate the two smallerturn diameters receptive of only the smallest diameter, and terminatingat its closed end in an opening of a size intermediate the two largerturn diameters and receiving and supporting the intermediate diametersize turns.

6. A key-switch assembly for producing chords in an electrical musicalinstrument, comprising in combination: an electrically conductiveapertured plate; a series of electrically conductive key elements, eachreciprocably supported in electrical contact with said plate and eachextending through a separate aperture therein; a series of more thanthree electrical conductors lying in a plane parallel to said plate andextending between said key elements and electrically insulatedtherefrom, said conductors being adapted to be connected tovariousfrequency signal sources; and electrically conductive engagingarm means secured to each of said key elements and electrically coupledtherethrough to said plate and extending therefrom transversely to saidconductors and transversely to the direction in which each key elementis reciprocable for engagement with a plurality of said conductors inresponse to reciprocation of one of said key elements.

7. In a keyed electrical musical instrument having a plurality of signalsources whose frequencies severally comprise major triads of root,third, and fifth notes, the

improvement in combination therewith of: an electrical- ,ly conductiveapertured plate; a series of electrically con- `ductive key elements,each reciprocably supported in electrical contact with said plate andeach Vextending through a separate aperture therein; a series ofelectrical conductors lying in a plane parallelV to said plate andrespectively connected to said signal sources and extending between saidkey elements and electrically insulated therefrom; and electricallyconductive engaging arm means for each of said key elements and securedthereto and electrically coupled therethrough to said plate, the armmeans of each of said key elements extending therefrom transversely tothree of said conductors whose frequencies comprise one major triad, andtransversely to the direction in which the key element is reciprocablefor engagement with said three conductors in response to reciprocationofthe key element; the conductor whose signal source has the fifth notefrequency of said one major triad also being engageable by the engagingarm means of another one of said key elements where its frequencycomprises the root note signal of a different chord.

S. In a keyed electrical musical instrument having a plurality of signalsources whose frequencies severally comprise major triads of root,third, and fifth notes, the improvement.inicombination therewith of: anelectrically conductive apertured plate; a series of electrically conlductive key elements, each reciprocably supported in electrical contactwith said plate and each extending through a separate aperture therein;a series of electrical conductors lying in a plane parallel to saidplate and respectively connected to said signal sources and extendingbetween said key elements and electrically insulated therefrom; andelectrically conductive engaging arm means for each of said key elementsand secured thereto and electrically coupled therethrough to said plate,the arm means of each of said key elements extending therefromtransversey `to three of said conductors Whose frequencies comprise onemajor triad, and transversely to the direction in which the key elementis reciprocable for engagement with said three conductors in response toreciprocation of the key element; those of said three conductors, whosesignal source frequency appears in another chord of the same root note,being also engageable by the engaging arm means of another one of saidkey elements.

9. ln a keyed electrical musical instrument having a plurality of signalsources whose frequencies jointly comprise a musical scale, theimprovement in combination therewith of: an electrically conductiveapertured plate; a series of electrically conductive key elements, eachre- Vciprocably supported in electrical contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying in a plane parallel to said plate and respectivelyconnected to said signal sources and extending between said key elementsand electrically insulated therefrom; and electrically conductiveengaging arm means for each of said key elements and secured thereto andelectrically coupled therethrough to said plate, the arm means of eachof said key elements extending therefrom transversely to three of saidconductors whose frequencies comprise a chord, and transversely to thedirection in which the key element is reciprocable for engagement withsaid three conductors in response to reciprocation of the key element;one of said three conductors being engageable by the arm means of aplurality of said chord-producing key elements which engage a pluralityof root note conductors.

10. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies jointly comprise a musical scale, theimprovement in combination therewith of: an electrically conductiveapertured plate; a series of electrically conductive key elements, eachreciprocably supported in electrical contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying in a plane parallel to said plate and respectivelyconnected to said signal sources and extending between said key elementsand electrically insulated therefrom; and electrically conduclll tiveengaging arm means for each of said key elements and secured thereto andelectrically coupled therethrough to said plate, the arm means of eachof said key elements extending therefrom transversely to three of saidconductors whose frequencies comprise a chord, and transversely to thedirection in which :the key element is reciprocable for engagement withsaid three conductors in response to reciprocation of the key element;one of said conductors being engageable by said arm means of four ofsaid key elements to provide the iiatted third note of both the minorchord and the diminished seventh chord of a certain root note, thedominant seventh note of the dominant seventh chord whose root note is afifth below said certain root note, and the raised fifth note of theaugmented chord whose root note is a fifth above said certain root note.

11. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies jointly comprise a musical scale, theimprovement in combination therewith of: an electrically conductiveapertured plate; a series of electrically conductive key elements, eachreciprocably supported in electrical Contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying in a plane parallel to said plate and respectivelyconnected to said signal sources and extending between said key elementsand electrically insulated therefrom; and electrically conduce tiveengaging arm means for each of said key elements and secured thereto andelectrically coupled therethrough to said plate, the arm means of eachof said key elements extending therefrom transversely to three of saidconductors whose frequencies comprise a chord, and transversely to thedirection in which the key element is reciprocable for engagement withsaid three conductors in response to reciprocation of the key element;one of said conductors being engageable by said arm means of said keyelements to provide at least two notes from the group consisting of theflatted third note of either the minor chord or of the diminishedseventh chord of a certain root note, the dominant seventh note of thedominant seventh chord whose root note is a fifth below said certainroot note, and the raised fifth note of the augmented chord Whose rootnote is a fifth above said certain root note.

12. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements, each reciprocably supported in electricalcontact with said plate and each extending through a separate aperturetherein; a series ofelectrical conductors lying in a plane parallel tosaid plate and respectively connected to said signal sources andextending between said key elements and electrically insulatedtherefrom; land -electrically `conductive engaging arm means for each ofsaid key elements and secured thereto and electrically coupledtherethrough to said plate, the arm means of each of said key elementsextending therefrom transversely to three cf said conductors whosefrequencies comprise one major triad, and transversely to thedirectionfin which the key element is reciprocable for engagement withsaid three conductors in response to reciprocation of the key element;the conductor whose signal source has the fifth note frequency of saidone major triad also being engageable by the engaging arm means ofanother one of said key elements where its frequency comprises the rootnote signal of a different chord, said another one of said key elementsalso being engageable with other of said conductors whose signalfrequencies comprise the flatted third and iiatted fifth notes to rendersaid different chord a diminished chord.

13. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements, each reciprocably supported in electricalcontact with said plate and each extending through a separate aperturetherein; a series of electrical conductors lying in a plane parallel tosaid plate and respectively connected to said signal sources andextending between said key elements and electrically insulatedtherefrom; and electrically conductive engaging arm means for each ofsaid key elements and secured thereto and electrically coupledtherethrough to said plate, the arm means of each of said key elementsextending therefrom transversely to three of said conductors whosefrequencies comprise one major triad, and transversely to the directionin which the key element is reciprocable for engagement with said threeconductors in response to reciprocation of the key element; theconductors Whose signal sources have the fifth and third notefrequencies of said one major triad also being engageable by theengaging arm means of another one of said key elements to provide theroot note and the diminished seventh note signals of a different chord,said another one of said key elements also being engageable with otherof said conductors whose signal frequencies comprise the iiatted thirdand flatted fifth notes to render said different chord a diminishedseventh chord.

ld. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements, each reciprocably supported in electricalcontact with said plate and each extending through a separate aperturetherein; a series of electrical conductors lying in a plane parallel tosaid plate and respectively connected to said signal sources andextending between said key elements and electrically insulatedtherefrom; and electrically conductive engaging arm means for each ofsaid key elements and secured thereto and electrically coupledtherethrough to said plate, the arm means of each of said key elementsextending therefrom transversely to three of said conductors whosefrequencies comprise one major triad, and transversely to the directionin which the key element is reciprocable for engagement With said threeconductors in response to reciprocation of the key element; each of saidthree conductors being also engageable by the engaging arm means of afurther one of said key elements, said further one of said key elementsalso being -engageable with another conductor providing a signalfrequency comprising the dominant seventh note for also providing adominant seventh chord.

l5. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements, each reciprocably supported in electricalcontact with said plate andreach extending through a separate aperturetherein; a series of elongated normally straight flexible stretchableelectrical conductors supp0rted at both ends and normally lying in aplane parallel to said plate and respectively connected to said signalsources and extending between said key elements and electricallyinsulated therefrom; and electrically conductive engaging arm means foreach of said key elements and secured thereto and electrically coupledtherethrough to said plate, the arm means of each of said key elementsextending therefrom transversely to three of said conductors whosefrequencies comprise one major triad, and transversely to the directionin which the key element is reciprocable for engagement with said threeconductors in response to reciprocation of the key element, each of saidthree conductors being also engageable by the engaging arm means of afurther one of said key elements, said further one of said key elementsalso being engageable with another conductor providing a signalfrequency comprising the dominant seventh note for thereby alsoproviding a dominant seventh chord; said flexible stretchable conductorsbeing deflectable in response to said engagement effected byreciprocation of a iirst of said key elements, and a portion thereofbeing deiiectable an additional amount in response to beingsimultaneously engaged by the arm means of a second of said keyelements, whereby the dominant seventh note may be added to and removedfrom a major triad chord while said triad chord is continuallymaintained.

16. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrical- 1y conductive apertured plate; a series ofelectrically conductive key elements, each reciprocably supported inelectrical contact with said plate and each extending through a separateaperture therein; a series of electrical conductors lying in a planeparallel to said plate and respectively connected to said signal sourcesand extending between said key elements and electrically insulatedtherefrom; said conductors being so arranged that groups of threeadjacent conductors have signal frequencies which comprise the root,third, and fifth notes of a major triad, the fifth note conductors of aplurality of said groups being the root note conductors of successiveadjacent triads; and electrically conductive engaging arm means for eachof said key elements and secured thereto and electrically coupledtherethrough to said plate, the arm means of each of said key elementsVextending therefrom transvcrselyto one of said conductor groups andtransversely to the direction in which the key element is reciprocablefor engagement with said one conductor group in response toreciprocation of the key element.

17. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements arranged in a plurality of rows, eachreciprocably supported in electrical contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying parallel to said rows in a plane parallel to said plateand respectively connected to said signal sources and extending betweensaid key elements and electrically insulated therefrom; said conductorsbeing so arranged that groups of three adjacent conductors have signalfrequencies which comprise the root, third, and fifth notes of a majortriad, the fifth note conductors of a plurality of said groups being theroot note conductors of successive adjacent triads; electricallyconductive engaging arm means for each of said key elements in said rowsand secured thereto and electrically coupled therethrough to said plate,the arm means of each of said key elements extending therefromtransversely to said conductors and transversely to the direction inwhich the key element is reciprocable; the arm means of one of said keyelements of each row being engageable with one of sai-d conductor groupsrespectively; and additional elongated electrical conductors disposedadjacent to other key elements in each of said rows and electricallyinsulated therefrom, said additional conductors having other signalfrequencies; said other key elements in each of said rows beingengageable through its arm means with at least one of said additionalconductors and at least one conductor of said one group in response toreciprocation thereof.

18. In a keyed electrical musical instrument having a plurality ofsignal sources whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key elements arranged in a plurality of rows, eachreciprocably supported in electrical Contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying parallel to electrically conductive engaging arm meansfor each ofI said key elements in said rows and secured thereto andelectrically coupled therethrough to said plate, the arm means of eachof said key elements extending therefrom transversely to said conductorsand transversely to the direction in which the key element isreciprocable; the arm means of one of said key elements of each rowbeing engageable with one of said conductor groups respectively; andadditional elongated electrical conductors disposed adjacent to otherkey elements in each of said rows and electrically insulated therefrom,certain of said additional conductors being disposed parallel to eachother and extending in spaced transverserelation to three of saidconductor groups, said addition conductors having other signalfrequencies; said other key elements in each of said rows beingengageable through its arm means with at least one of said additionalconductors and at least one conductor of said one group in response toreciprocation thereof; each of said certain additional conductors beingengaged by the arm means of at least one of said other key elements ineach of three adjacent rows.

` 19. A key-switch assembly for producing chords in an electricalmusical instrument, comprising in combination: an electricallyconductive apertured plate; a series of electrically conductive keyelements, each reciprocably supported in electrical contact with saidplate and each extending through a separate aperture therein; a iirstseries of more than three electrical conductors lying parallel to eachother in a plane parallel to said plate, and a second series of morethan three electrical conductors lying parallel to each other in a planeparallel to said plate and each extending in spaced transverse relationto said first series of conductors, said conductors extending betweensaid key elements and electrically insulated therefrom, said conductorsbeing adapted to be connected to various-frequency signal sources; andelectrically conductive engaging arm means secured to each of said keyelements and electrically coupled therethrough to said plate andextending therefrom transversely to said conductors and transversely tothe direction in which each key element is reciprocable for engagementwith a plurality of said conductors in response to reciprocation of oneof said key elements.

20. In a keyed electrical musical instrument having a plurality ofsignal sources Whose frequencies severally comprise major triads ofroot, third, and fifth notes, the improvement in combination therewithof: an electrically conductive apertured plate; a series of electricallyconductive key element-s arranged in a plurality of rows, eachreciprocably supported in electrical contact with said plate and eachextending through a separate aperture therein; a series of electricalconductors lying parallel to said rows in a plane parallel to said plateand respectively connected to said signal sources and extending betweensaid key elements and electrically insulated therefrom; said conductorsbeing so arranged that groups of three adjacent conductors have signalfrequencies which comprise the root, third, and fifth notes of a majortriad, the fifth note conductors of a plurality of said groups being theroot note conductors of successive adjacent triads; electricallyconductive engaging arm means for each of said key elements in said rowsand secured thereto and electrically coupled therethrough to said plate,the arm means of each of said key elements extending therefromtransversely to said conductors and transversely to the direction inwhich the key element is reciprocable; the arm means of one of said keyelements of each row areasp? being engageable with one of said conductorgroups respectively; and additional elongated electrical conductorsdisposed adjacent to other key elements in each of said rows andelectrically insulated therefrom, certain of said additional conductorsbeing disposed parallel to each other and extending in spaced transverserelation to at least two of said conductor groups, said additionalconductors having other signal frequencies with said certain additionalconductors providing the dominant seventh note frequency; said other keyelements in each of said rows being engageable through its arm meanswith at least-one of said additional conductors and at least oneconductor of said one group in response to reciprocation thereof, one ofsaid other key elements in one row being engageable through its armmeans with the conductors of said one group and with the correspondingone of said certain additional conductors to provide a dominant seventhchord, one of said other key elements in an adjacent row beingengageable through its arm means with the root and fth note conductorsof its row and with said one of said certain additional conductors toprovide a minor chord, and said one of said other key elements beingselectively simultaneously reciprocable with said one other key elementto add a ninth note to said dominant seventh chord.

21. A key-switch comprising in combination: an electrically conductiveapertured plate; a reciprocably-supported electrically-conductive keyelement extending through the plate aperture; an electrically conductivespring surrounding one end of said key element and effecting electricalcontinuity between said key element and said plate, and continuallyurging said key element in one direction; an elongated helicalelectrically conductive extension spring contact rigidly supported atboth its ends and disposed adjacent to said key element and electricallyin- 1? sulated therefrom; and an electrically conductive engaging armsecured to said key element and electrically coupled through said springto said plate and extending from said key element transversely to saidspring contact and transversely to the direction in which said keyelement is reciprocable and selectively engageable with said springcontact in response to reciprocation of said key element in the oppositedirection, said spring contact being yieldable intermediate its ends inresponse to being engaged by said engaging arm, said spring applying aforce to said key element which is somewhat greater than the force bywhich said spring contact resists yielding in response to saidengagement and which provides the feel to manual movement of said keyelement.

References Cited by the Examiner UNITED S ATES PATENTS GEORGE N. WESTBY,Primary Examiner.

LAWRENCE V. EFNER, ARNOLD RUEGG,

. Examiners.

1. A KEY SWITCH COMPRISING IN COMBINATION: AN ELECTRICALLY CONDUCTIVEPLATE; AN ELECTRICAL CONDUCTIVE KEY ELEMENT RECIPROCABLY SUPPORTED INELECTRICAL CONTACT WITH SAID PLATE; A PAIR OF SEPARATE ELECTRICALCONDUCTORS DISPOSED ADJACENT TO BUT SPACED DIFFERENT DISTANCES FROM SAIDKEY ELEMENT AND ELECTRICALLY INSULATED THEREFROM AND FROM EACH OTHER;AND AN ELECTRICALLY CONDUCTIVE ARM ELECTRICALLY CONDUCTIVELY SECURED TOSAID CONDUCTIVE KEY ELEMENT AND EXTENDING THEREFROM TRANSVERSELY TO SAIDCONDUCTORS AND TRANSVERSELY TO THE DIRECTION IN WHICH SAID KEY ELEMENTIS RECIPROCABLE AND SELECTIVELY ENGAGEABLE SIMULTANEOUSLY WITH BOTH SAIDCONDUCTORS IN RESPONSE TO RECIPROCATION OF SAID KEY ELEMENT; AND ANINSULATOR ENGAGEABLE WITH BOTH SAID ARM AND THAT ONE OF SAID CONDUCTORSWHICH IS NEARER TO SAID KEY ELEMENT IN A MANNER TO PRECLUDE ELECTRICALCONTINUITY THEREBETWEEN DURING SAID ENGAGEMENT.